Optical disc, recording device and reproducing device

ABSTRACT

Optical discs formatted to record plural audio streams of different content for reproduction with a single video stream can result in audio output of content unexpected by the user depending upon the audio stream configuration contained in the AV stream reproduced. This can confuse and cause the user to change the audio output after reproduction starts. To prevent this, information indicating the type of audio stream configuration contained in each AV stream on the optical disc is stored with each audio stream. This audio stream type information is presented to the user on the same screen from which an AV program is selected for playback. The user can thus know before playback starts what audio stream channel is preselected for playback, and can change the audio channel as desired before playback starts.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a readable and writable optical disc,and to a recording device and a reproducing device for the optical disk.More particularly, our invention relates to an optical disc forrecording multimedia data including moving picture data, still imagedata, and audio data, and to a recording device and a reproducing devicefor this optical disc.

2. Description of the Related Art

Rewritable optical discs have for years had a maximum storage capacityof approximately 650 MB, but this has been changed by the development ofphase change type DVD-RAM discs with a capacity of several gigabytes.Combined with the adoption of MPEG standards for encoding digital AVdata, and particularly MPEG-2, DVD-RAM is widely anticipated as arecording and reproducing medium with application in the AV industry aswell as the computer industry. More specifically, DVD-RAM media areexpected to replace magnetic tape as the storage medium of choice for AVrecordings.

A. DVD-RAM

Increases in the storage density of rewritable optical disc media overthe last few years have made it possible to use such media forapplications ranging from storing computer data and recording audio datato recording image data, including movies.

The signal recording surface of a conventional optical disc is typicallyformatted with lands and grooves, one of which is used as a guide groovefor signal recording and reproducing. The data signal is then recordedusing only the land or the groove. With the advent of the land andgroove recording method, however, it became possible to record signalsto both the land and groove. This development approximately doubled thestorage capacity of the disc.

Further development of a zone CLV (constant linear velocity) methodsimplified and made it easy to implement a CLV recording and reproducingtechnique, an effective means of further increasing the recordingdensity.

A major topic left for future development is how to use such potentiallyhigh capacity optical disc media to record AV data containing image datato achieve new functions and performance far surpassing conventional AVproducts.

With the introduction of high capacity rewritable optical disc media,optical discs are widely expected to replace conventional tape media forrecording and reproducing AV content. The transition from tape to discrecording media is also expected to greatly affect both the performanceand functions of AV recording and reproducing products.

One of the greatest benefits of a transition to disc is a significantimprovement in random access performance. While random access to tapecontent is possible, it generally takes on the order of minutes torewind a full tape. This is several orders slower than the typical seektime of optical disc media, which is on the order of at most several tenmilliseconds. Tape is therefore considered, for practical purposes, notto be a random access medium.

The random access capability of optical disc media has also madepossible distributed, that is, noncontiguous, recording of AV data,which is not possible with conventional tape.

FIG. 34 is a block diagram of the drive device of a DVD recorder. Asshown in FIG. 34, this DVD recorder comprises an optical pickup 11 forreading data from the disc 10, an ECC (error correction code) processor12, track buffer 13, switch 14 for changing track buffer input/output,encoder 15, and decoder 16. An enlarged view of the disc 17 format isalso shown.

As indicated by the disc 17 format, the smallest unit used for recordingdata to a DVD-RAM disc is the sector, which is 2 KB. Sixteen sectors arecombined as one ECC block, to which the ECC processor 12 applies errorcorrection coding.

The track buffer 13 is used for recording AV data at a variable bit ratein order to record AV data to a DVD-RAM disc more efficiently. While theread/write rate (Va) to a DVD-RAM disc is fixed, the bit rate (Vb) ofthe AV data is variable, based on the complexity of the AV data content(e.g., images if the AV data is video). The track buffer 13 is used toabsorb this bit rate difference. This means that the track buffer 13 isunnecessary if the AV data bit rate is also fixed, as it is in the VideoCD format.

This track buffer 13 can be even more effectively used by dispersedplacement of the AV data on the disc. This is explained with referenceto FIG. 35.

FIG. 35(a) shows the disc address space. If the AV data is recordeddivided between contiguous area A1 between addresses a1 and a2, andcontiguous area A2 between a3 and a4 as shown in FIG. 35(a), the AV datacan be continuously reproduced from these non-contiguous areas A1 and A2by supplying data accumulated in the track buffer 13 to the decoderwhile the optical head seeks from a2 to a3. This is shown in FIG. 35(b).

Once reading AV data starts from a1 at time t1, it is both input to thetrack buffer 13 and output from the track buffer 13 with dataaccumulating in the track buffer at the rate (Va−Vb), that is, thedifference between the input rate Va to the track buffer and the outputrate Vb from the track buffer. This continues to address a2 at time t2.Assuming that the data volume accumulated to the track buffer at thistime is B(t2), data supply to the decoder can continue until the dataB(t2) accumulated to the track buffer is depleted at time t3 at whichreading resumes from address a3.

In other words, if it is assured that a certain volume of data ([a1,a2]) is read before a seek operation is performed, AV data can becontinuously supplied to the decoder while the seek is in progress.

It should be noted that this example considers reading, that is,reproducing, data from DVD-RAM, but the same concept applies for writingor recording data to DVD-RAM.

It will thus be obvious that insofar as a specified amount of data isrecorded continuously to DVD-RAM disc, continuous reproduction andrecording is possible even if the AV data is noncontiguously recorded tothe disc.

B. MPEG

A common AV data format is described next below.

As noted above, AV data is recorded to DVD-RAM media using the MPEGinternational standard, also known as ISO/IEC 13818.

Even though DVD-RAM discs have a large, plural gigabyte, capacity, thisis still not sufficient for recording uncompressed digital AV data ofany duration. A way to compress and record AV data is thereforenecessary. This need was addressed by worldwide adoption of the MPEG(ISO/IEC 13818) standard for AV data compression. MPEG decoders(compression/decompression ICs) have also been realized with advances inIC devices. This has enabled the DVD recorder to handle MPEG compressionand decompression internally.

MPEG signal processing is able to achieve high efficiency datacompression chiefly as a result of the following two features.

First is that compression using a time correlation characteristicbetween frames (known as pictures in MPEG) is used in conjunction withconventional compression using a spatial frequency characteristic formoving picture data compression. Each video sequence of an MPEG videosignal stream is divided into one or more groups of pictures, each groupof pictures comprising one or more pictures of three different types:I-pictures (intraframe coded pictures), P-pictures (predictive-codedpictures, that is, intracoded with reference to a preceding picture),and B-pictures (bidirectionally predictive-coded pictures, that is,intraframe coded with reference to preceding and following pictures).

FIG. 36 shows the relationship between I, P, and B pictures. As shown inFIG. 36, P-pictures refer to temporally preceding I- or P-pictures inthe sequence, while B-pictures refer to the first preceding andfollowing I- or P-pictures. It should also be noted that becauseB-pictures reference an upcoming I- or P-picture, the display order ofthe pictures may not match the coding order of the pictures in thecompressed data bitstream.

The second feature of MPEG coding is that code size is dynamicallyallocated by picture unit according to the complexity of the image. AnMPEG decoder has an input buffer, and by accumulating data in thisdecoder buffer a large amount of code can be allocated to complex loimages that are difficult to compress.

Three types of audio coding are used for the audio portion of a DVD-RAMrecording: MPEG audio with data compression, Dolby Digital^((R)) (alsoknown as AC-3), and noncompressive linear pulse code modulation (LPCM).Both Dolby Digital^((R)) and LPCM are fixed bit rate coding methods, butMPEG audio coding can select from several compression rates on an audioframe basis, although audio compression is not as high as video streamcompression.

The resulting compressed video and audio streams are multiplexed to asingle stream using a method known as the MPEG system. FIG. 37 shows theorganization of an MPEG system stream. As shown in FIG. 37, each 2 KBsector comprises a pack header 41, packet header 42, and payload 43. TheMPEG system thus has a hierarchical structure comprising packs andpackets. Each packet comprises a packet header 42 and payload 43. AVdata is segmented from the beginning into blocks of an appropriate sizefor storage to the payload 43.

The packet header 42 records information referring to the AV data storedin the associated payload 43. More specifically, the packet header 42contains a stream ID for identifying the data stored in the associatedpacket, and a decoding time stamp (DTS) and presentation time stamp(PTS) identifying-the decoding time and presentation time of the datacontained in the payload in 90 kHz precision. If the decoding andpresentation are simultaneous, as in the case of audio data, the DTS canbe omitted.

A pack is a unit of plural packets. In DVD-RAM, however, there is onepack for each packet, and each pack therefore comprises a pack header 41and packet (containing a packet header 42 and payload 43).

The pack header contains a system clock reference (SCR) expressing with27 MHz precision the time at which the data contained in this pack isinput to the decoder buffer.

An MPEG system stream thus comprised is recorded one pack to a sector(=2048 bytes) on DVD-RAM.

A decoder for decoding the above-noted MPEG system stream is describednext below. FIG. 38 is a block diagram of an exemplary decoder model(P_STD) of an MPEG system stream decoder. Shown in FIG. 38 are thesystem time clock (STC) 51, that is, the internal reference clock fordecoder operation; a demultiplexer 52 for decoding (demultiplexing) thesystem stream; video decoder input buffer (video buffer) 53; videodecoder 54; re-ordering buffer 55 for temporarily storing I and Ppictures to absorb the difference in the coding (data) sequence andpresentation sequence that occurs between B pictures and I and Ppictures; a switch 56 for adjusting the output order of the I, P, and Bpictures buffered to the re-ordering buffer 55; an audio decoder inputbuffer (audio buffer) 57; and audio decoder 58.

This MPEG system decoder processes the above-noted MPEG system stream asfollows.

When the time indicated by the STC 51 and the SCR written to the packheader match, the pack is input to the demultiplexer 52. Thedemultiplexer 52 then interprets the stream ID in the packet header, andpasses the audio stream and video stream contained in the payload datato the appropriate decoder buffers. The PTS and DTS are also read fromthe packet header.

When the times indicated by the STC 51 and DTS match, the video decoder54 reads and decodes the picture data from the video buffer 53. I and Ppictures are stored to the re-ordering buffer 55 while B pictures arepresented directly to screen. If the picture being decoded by the videodecoder 54 is an I or P picture, the switch 56 switches to there-ordering buffer 55 to output the previous I or P picture from there-ordering buffer 55; if a B picture is decoded, the switch 56 switchesto the video decoder 54.

Similarly to the video decoder 54, the audio decoder 58 reads anddecodes one audio frame of data from the audio buffer 57 when the PTSmatches the STC 51 (a DTS is not recorded for audio data).

An exemplary method of multiplexing an MPEG system stream is describednext with reference to FIG. 39. Note that a sequence of video frames isshown in FIG. 39(a), the change in data storage to the video buffer isshown in FIG. 39(b), a typical MPEG system stream is shown in FIG.39(c), and an audio signal is shown in FIG. 39(d). Each of FIGS. 39 (a)to (d) are shown on a common time base (horizontal axis). The verticalaxis in FIG. 39(b) indicates the amount of data stored to the videobuffer. The bold line in this graph thus indicates the change over timein the buffered video data volume. The slope of this line is indicativeof the video bit rate, and shows that data is input to the video bufferat a constant rate. The decrease in buffered data at regular intervalsindicates the progression of data decoding. The intersection of thedotted line extension of the graphed line with the time base (horizontalaxis) indicates the time at which video frame transfer to the videobuffer begins.

MPEG encoding is described next using by way of example coding a compleximage A in the video data stream. As shown in FIG. 39(b), image Arequires a large coding block, and data transfer to the video buffermust therefore begin from a time t1 before the image A decoding time.Note that the time from data input start time t1 to decoding is referredto as vbv_delay below. AV data is thus multiplexed to the position(time) of the shaded video pack.

Unlike video data, audio data does not require dynamic coding sizecontrol. It is therefore not necessary for audio data transfer to startat a similarly advanced time before decoding starts, and audio data isthus typically multiplexed only slightly before decoding starts. Videodata is thus multiplexed to the MPEG system stream before the audiodata.

It should be further noted that data can be accumulated to the bufferfor a limited time in the MPEG system. More specifically, the MPEGsystem standard requires all data other than still image data be outputto the decoder from the buffer within one second of being stored to thebuffer. This means that there is at most a one second offset betweenvideo data and audio data multiplexing (or more precisely, the timerequired for video frame reordering).

It will also be obvious that while the MPEG system stream is describedabove with video data preceding the audio, the audio can theoreticallyprecede the video. This type of stream can be purposely generated byusing for the video data simple images to which a high compression ratecan be applied, and transferring the audio data earlier than required.Even in this case, however, the audio can precede the video by at mostone second due to the restrictions imposed by the MPEG standard.

Audio Stream Format and Reproduction

The format of the audio stream and a method for audio streamreproduction are described next below.

As described above, data is recorded and reproduced from a linearrecording area in sequential access media such as magnetic tape. Atypical method for recording an audio stream to a plurality of tracks ona single tape is described next below with reference to FIG. 41. In thisexample a maximum of two audio streams, shown as audio stream 1 andaudio stream 2, can be recorded for a single video stream. In thisexample audio stream 1 is a single audio channel, generally known as amonaural audio channel, and audio stream 2 comprises two audio channels,such as a stereo audio signal or two monaural streams enabling abilingual recording. It is also possible to record only one of these twoaudio streams (audio stream 1 or audio stream 2) or to record no audiostream. However, reducing the amount of audio recorded cannot be used asa means for increasing the video storage capacity of the tape. In otherwords, the audio stream recording area, i.e., the audio track space, isreserved exclusively for audio content and cannot be used for any otherapplication even when no audio stream is actually recorded. The user canalso select which of the two audio streams and channels to play, and theaudio stream or channel selected by the user is reproducedsimultaneously with the video.

DVD-RAM and other disc media, however, allow for more flexible audiostream recording and reproduction. The number of audio streams andchannels recorded simultaneously with a video stream can be varied forthe plurality of audio streams recorded to a disc.

FIG. 42 shows some of the ways in which the audio stream content can bevaried with the video stream in a disc media. For example, AV stream 1in FIG. 42(a) comprises one audio stream for the video stream, and theaudio stream in this case has only one channel.

AV stream 2 in FIG. 42(b) similarly comprises one audio stream for thesame video stream, but the audio stream in this case comprises twochannels, i.e., main and sub audio channels. In this case the audiostream contains two selectively reproducible audio channels, a firstaudio channel containing the main audio (such as a first language), anda second audio channel containing the auxiliary audio data of the subchannel (such as a second language).

AV stream 3 in FIG. 42(c) comprises two audio streams for the videostream. In this case audio stream 1 is a single monaural channel whileaudio stream 2 contains two channels. The beginning of this audio stream2 is recorded in stereo and then switches to dual monaural audiocontent. More specifically, audio stream 2 in this example comprises atleast two of the following three audio content areas: a second (stereo)area containing first and second simultaneously reproduced audio channeldata; a first (dual monaural) area containing first and second audiochannels of which only one is selected and reproduced; and a third(monaural) area containing only one audio channel.

It will also be obvious that audio content is not limited to thesestereo, dual monaural, and monaural types, and this audio stream 2 issimply illustrative of an audio stream containing a mix of differentaudio types. In the example shown in FIG. 42(c), audio stream 2 containsa stereo and a dual monaural area. Exemplary stereo content might be thecommercials in a television broadcast while the dual monaural contentcontains separate audio streams of a bilingual broadcast in, forexample, Japanese and English.

As noted above the relationship between video and audio streams onDVD-RAM and other disc media is flexible with the audio streamconfiguration being easily adapted according to the application andobjective of the plural AV streams recorded to any same disc. It shouldbe noted here that the AV stream configuration shown in FIG. 42 mimics atape track configuration simply for ease of illustration andunderstanding. The actual AV stream configuration is a multiplexed bitstream of video stream data and one or more audio streams as shown inthe MPEG system stream in FIG. 39(c).

Problem to be Solved

The object of the present invention is to provide a DVD recorder thatsolves the following problems hindering obtaining maximum performancefrom DVD-RAM media, a high capacity rewritable storage medium widelyanticipated as the next generation in AV recording media.

As described with reference to FIG. 42(a) to (c), one or a plurality ofaudio streams can be freely recorded to DVD-RAM media with each audiostream containing a variable number of channels. The user can tell thenumber of audio streams and the channel configuration thereof byreproducing the AV stream to which this audio stream is recorded, butcannot know this information by simply loading the disc into the DVD-RAMdisc player.

An object of the present invention is therefore to provide a disc formatwhereby the user can know the audio stream configuration of a recordedAV stream before actually reproducing the AV stream.

Our invention further makes it possible for the user to know the audiostream configuration for each of one or a plurality of AV streamsrecorded to a DVD-RAM disc when the disc is loaded into a DVD-RAM discplayer.

The greatest problem confronted by enabling a DVD recorder to record aflexible correlation between video streams and audio streams so thatdifferent audio stream configurations can be achieved for each AV streamon the disc is how to manage the data internally and how to present thedata to the user.

The internal data management technique must be able to manage a varietyof audio stream configurations while also achieving recording,reproducing, and editing functions without introducing incompatibilitiesand content mismatches.

A diverse range of audio stream configurations enables finite recordingspace (capacity) to be used effectively, and enables recording variousAV streams according to particular user objectives, but at the same timecan introduce confusion. In other words, when a user wants to play aparticular AV stream, the user cannot select the appropriate audiostream and audio channel(s) if the user does not know what audio streamconfiguration was recorded for the desired AV stream. For example, ifboth Japanese and English audio streams are recorded and both areselectable so that the user can listen in either language, the AV streamcould be reproduced in the language not desired by the user as a resultof how the disc player is set up. Depending upon the circumstances it isalso possible for the user to manually reselect the desired audio streamwhen the user realizes that the undesired audio stream is beingreproduced.

There is therefore a need for a method of correctly selecting thedesired audio stream and audio channel at the same time the desired AVstream is selected for reproduction.

It is therefore an object of our invention to provide a rewritable disc,such as a DVD-RAM disc, formatted such that information about the audiostream and audio channel configuration can be appropriately presented tothe user using management information recorded to the disc when aplurality of audio stream configurations is recorded for one videostream, and an audio stream to be reproduced can be automaticallyselected according to selection information defined by the user.

SUMMARY OF THE INVENTION

To achieve the above object, our invention relates to an optical discfor storing an AV stream containing a video stream and at least oneaudio stream, and management information for managing the AV stream.More particularly, our invention provides such an optical disc in whichthe audio stream recorded to the optical disc comprises an audio channelarea containing first and second audio channels, one of which isselectively reproduced. In addition, the management information storespreference information indicative of whether the first audio channeldata or second audio channel data is preferentially reproduced whenreproducing the audio channel area.

Further preferably, the audio stream contains at least two of thefollowing areas: a first area containing first audio channel data andsecond audio channel data, one of which is selectively reproduced; asecond area containing simultaneously reproduced first audio channeldata and second audio channel data; and a third area containing data forone audio channel. In this case, the management information additionallycontains application information indicating that two or more differentaudio stream areas are contained in one audio stream.

Our invention further provides a recording device for recording to anoptical disc an AV stream containing a video stream and at least oneaudio stream, and management information for managing the AV stream.This recording device has an encoder (7804) for encoding an audio streamhaving an area containing first audio channel data and second audiochannel data, one of which is selectively reproduced; a controller(7802) for generating management information containing preferenceinformation indicating whether the first audio channel data or secondaudio channel data is to be preferentially reproduced when the audiochannel area is reproduced; and drive means (7807, 7808) for recordingthe encoded audio stream and management information to a data area ofthe optical disc.

Further preferably, the encoder further encodes an audio streamcontaining at least two of the following areas: a first area containingfirst audio channel data and second audio channel data, one of which isselectively reproduced; a second area containing simultaneouslyreproduced first audio channel data and second audio channel data; and athird area containing data for one audio channel. The controller in thiscase generates management information containing application informationindicating that two or more different audio stream areas are containedin one audio stream.

Our invention also provides a playback device for reproducing an AVstream containing a video stream and at least one audio stream, andmanagement information for managing the AV stream, from an optical disc.This playback device has reading means (7807, 7808) for readingmanagement information from a data area of the optical disc; extractionmeans (7802, Step #26) for extracting preference information containedin the management information; and a decoder (7806) for selecting anddecoding audio channel data indicated by the preference information. Thepreference information indicates whether the first audio channel data orsecond audio channel data is to be preferentially reproduced whenreproducing the area containing the first audio channel data or secondaudio channel data of which one is selectively reproduced.

Further preferably, this playback device additionally has an outputmeans (7805) for displaying the preferred audio channel determined fromthe preference information.

Yet further preferably, the extraction means of this playback devicealso extracts application information indicating two or more areas ofdifferent type are mixed in a single audio stream; and the output meansdisplays information indicating that a mixture of audio types isrecorded to the AV stream.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bereadily understood from the following detailed description taken inconjunction with preferred embodiments thereof with reference to theaccompanying drawings, in which like parts are designated by likereference numerals and in which:

FIG. 1 shows the logical structure of a disc according to a preferredembodiment of the present invention;

FIG. 2 shows the internal structure of an AV file for movies;

FIG. 3 shows the internal structure of an AV file for still images;

FIG. 4 shows the relationship between AV data and managementinformation;

FIG. 5 shows the structure of the RTR_VMG block;

FIG. 6 shows the structure of the RTR_VMGI block;

FIG. 7 shows the VERN and TM_ZONE format;

FIG. 8 shows the structure of the PL_SRP block;

FIG. 9 shows the PL_TY and PL_CREATE format;

FIG. 10 shows the PTM format;

FIG. 11 shows the S_VOB_ENTN format;

FIG. 12 shows the structure of the M_AVFIT block;

FIG. 13 shows the V_ATR and A_ATR format;

FIG. 14 shows the SP_ATR and SP_PLT format for movies;

FIG. 15 shows the structure of the M_AVFI block;

FIG. 16 shows the structure of the M_VOBI block;

FIG. 17 shows the VOB_TY format;

FIG. 18 shows the structure of the TMAPI block;

FIG. 19 shows the VOBU_ENT format;

FIG. 20 shows the structure of the S_AVFIT block;

FIG. 21 shows the V_ATR and OA_ATRS_AA_STI format;

FIG. 22 shows the SP_ATR and SP_PLT format for still images;

FIG. 23 shows the structure of the S_AVFI block;

FIG. 24 shows the structure of the S_VOB_ENT block;

FIG. 25 shows the S_VOB_ENT_TY format;

FIG. 26 shows the structure of the UD_PGCIT block;

FIG. 27 shows the structure of the TXTDT_MG block;

FIG. 28 shows the structure of the PGCI block;

FIG. 29 shows the PG_TY format;

FIG. 30 shows the structure of the CI block;

FIG. 31 shows the C_TY format;

FIG. 32 shows the structure of the C_EPI block;

FIG. 33 shows the EP_TY1 format;

FIG. 34 is a block diagram of a DVD recorder drive;

FIG. 35(a) shows the volume address space of a disc, and FIG. 35(b)shows the change in data accumulation in the track buffer;

FIG. 36 shows the correlation between picture types in an MPEG videosystem stream;

FIG. 37 shows the structure of an MPEG system stream;

FIG. 38 is a block diagram of an MPEG system decoder (P_STD);

FIG. 39(a) shows video data, FIG. 39(b) shows the change in dataaccumulation in the video buffer, FIG. 39(c) shows the MPEG systemstream, and FIG. 39(d) shows the audio data;

FIG. 40 is a block diagram of a DVD recorder;

FIG. 41 is used to describe the audio stream configuration in aconventional AV stream,

FIG. 42A and FIG. 42B and FIG. 43C are used to describe audio streamconfigurations in an exemplary AV stream;

FIG. 43 shows the relationship between management information stored todisc and a first exemplary audio stream configuration;

FIG. 44 shows the relationship between management information stored todisc and a second exemplary audio stream configuration;

FIG. 45 shows the relationship between management information stored todisc and a third exemplary audio stream configuration;

FIG. 46 is used to describe the management information structure writtento optical disc;

FIG. 47 is a flow chart of an operation for recording audio datamanagement information to optical disc;

FIG. 48 is a flow chart of an operation for presenting a program listindicating the content of a disc inserted to the disc player;

FIG. 49 is a flow chart of an operation for reproducing a programrecorded to a disc inserted to the disc player; and

FIG. 50 shows an exemplary program list generated from a disc insertedto the disc player and presented for the user.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A DVD recorder and DVD-RAM disc are described below as a preferredembodiment of the present invention with reference to the accompanyingfigures.

Logical Structure of DVD-RAM

The logical structure of a DVD-RAM disc is described first below withreference to FIG. 1. FIG. 1 shows the physical sector address area ofthe disc, and the structure whereby data is recorded to the disc as partof a file system.

The physical sector address area of the disc starts with a lead-in areato which a reference signal for servo stabilization, and an ID signalfor differentiating DVD-RAM media from other media, are recorded. Theuser data area follows the lead-in area. Logically valid data isrecorded to the user data area. A lead-out area ends the physical sectoraddress area; a reference signal is also recorded here.

File system management information, called volume information, isrecorded at the beginning of the user data area. The file system is notdirectly related to the present invention, and description thereof isthus omitted below. It should be noted, however, that by using a filesystem, data recorded to the disc can be managed as files and adirectory to the files as shown in FIG. 1.

All data handled by the DVD recorder is filed under the DVD_RTRdirectory directly below the root directory as shown in FIG. 1.

Files handled by a DVD recorder can be grouped into two broadcategories: a management information file (RTR.IFO file) and one or moreAV files (RTR_MOV.VRO file, RTR_STO.VRO file).

AV files are recorded as an RTR_MOV.VRO file recording moving picturecontent (referred to as video below), or an RTR_STO.VRO file recordingstill image data and simultaneously recorded audio data.

FIG. 2 shows the file structure of an RTR_MOV.VRO file recording videocontent. As shown in FIG. 2, MPEG program streams (M_VOB (Movie VideoObject)) are arranged in recording sequence in the RTR_MOV.VRO file.

Each program stream (M_VOB) is built from a plurality of Video ObjectUnits (VOBU), each with a video reproduction time of 0.4 sec. to 1.0sec.

Each VOBU comprises a number of video packs (V_PCK), audio packs(A_PCK), and subpicture packs (SP_PCK); each pack is 2 KB.

The video data in each VOBU further comprises one or more Group ofPictures (GOP). The GOP is the decoding unit for MPEG video, starts withan I-picture, and contains plural P- or B-pictures.

FIG. 3 shows the structure of an RTR_STO.VRO file for recording stillimages and audio data. As shown in FIG. 3, an RTR_STO.VRO file containsS_VOB (Still Picture Video Objects), the MPEG program stream for stillimages, arranged in recording sequence.

The greatest difference between an S_VOB and M_VOB is that an S_VOBrecords still image data instead of moving picture data, and the stillimage data (video part) is followed by the audio data (audio part)instead of multiplexing the video and audio.

An S_VOB also contains one VOBU, which comprises a V_PCK, A_PCK, andSP_PCK.

AV Data and Management Information

The relationship between M_VOB, S_VOB, and management information isdescribed next below with reference to FIG. 4.

As described above, there are two types of AV data, M_VOB and S_VOB.Management information M_VOBI for each M_VOB is stored for each M_VOBwhere the M_VOBI records attributes of the corresponding M_VOB.Individually managing S_VOBs, however, would greatly increase the amountof management information. Management information S_VOGI is thereforeused to manage a group S_VOG containing plural S_VOB units. This S_VOGIrecords attributes for the corresponding S_VOB group.

What is important to note here is that MPEG stream data does not have alinear correlation between time and data size. As noted above, the MPEGsystem stream is compressed using temporal correlation characteristicsand variable length coding techniques (including variable bit ratecoding) in order to achieve high compression efficiency. As a resultthere is not necessarily a direct correlation between time and data size(address).

Therefore, an M_VOBI also contains a filter (TMAP) for converting timeand address information, and an S_VOGI also contains a filter (S_VOBEntries) for converting a still image number in an S_VOG group andaddress.

Management information for the reproduction sequence is described nextbelow.

The reproduction sequence is defined as a program chain (PGC) orsequence of cells describing all or part of a range of M_VOB or S_VOGblocks.

The reproduction sequence can be either of two types: an original PGCreferring to all AV data on the disc, or a user-defined PGC defining auser-selected reproduction sequence of AV data on the disc. Note that aplurality of user-defined PGC can be recorded.

The original PGC is also called a Program Set having a Program layerlogically bundling a plurality of cells.

A user-defined PGC is also called a Play List. Unlike an original PGC, aPlay List does not have a Program layer.

Management Information File

The content of the management information file RTR.IFO is described nextbelow with reference to FIG. 5 to FIG. 33.

RTR_VMG (FIG. 5)

The VR_MANGR.IFO file contains real-time recording video managementinformation RTR_VMG. RTR_VMG comprises seven tables: RTR_VMGI, M_AVFIT,S_AVFIT, ORG_PGCI, UD_PGCIT, TXTDT_MG, and MNFIT.

These seven tables are described in detail next below.

RTR_VMGI (FIG. 6)

Real-time recording video management information RTR_VMGI includes videomanagement information table VMGI_MAT and play list search pointer tablePL_SRPT.

VMGI_MAT (FIG. 6)

The video management information management table VMGI_MAT stores thefollowing information relating to the entire disc. The reproducingdevice and recording device, referred to as simply disc player andrecorder, respectively, below, first read this VMGI_MAT to detect theoverall structure of the disc.

VMG_ID (video management identifier)

Stores the identifier DVD_RTR_VMGO identifying the disc as storing videorecording data.

RTR_VMG_EA (RTR_VMG end address)

Stores the RTR_VMG end address.

VMGI_EA (VMGI end address)

Stores the VMGI end address.

VERN (version number)

Records the version number of the recording format of the stored videorecording data according to the format shown in FIG. 7.

TM_ZONE (time zone)

Records the time zone used for all time information recorded to thedisc. As shown in FIG. 7, the TM_ZONE stores a time zone stamp TZ_TYindicating whether time information is based on Greenwich Mean Time or aregional time standard (such as Eastern Standard Time (EST) or JapanStandard Time (JST)), and a time zone offset TZ_OFFSET recording thetime difference to Greenwich Mean Time.

STILL_TM (still time)

Stores the still time used for presenting still images without sound.

CHRS (character set code for primary text display)

Defines the character set code to use for primary text displays(described below).

M_AVFIT_SA (M_AVFIT start address)

Stores the start address of the movie AV file information table M_AVFIT.This start address is used in the seek operation for accessing theM_AVFIT table.

S_AVFIT_SA (S_AVFIT start address)

Stores the start address of the still image AV file information tableS_AVFIT. This start address is used in the seek operation for accessingthe S_AVFIT table.

ORG_PGCI SA (ORG_PGCI start address)

Stores the start address of the original PGC information. This startaddress is used in the seek operation for accessing the original PGC.

UD_PGCIT_SA (UD_PGCIT start address)

Stores the start address of the user-defined PGC information table. Thisstart address is used in the seek operation for accessing theuser-defined PGC information table.

TXTDT_MG_SA (TXTDT_MG start address)

Stores the start address of the text data management informationTXTDT_MG. This start address is used in the seek operation for accessingthe text data management information TXTDT_MG.

MNFIT_SA (MNFIT start address)

Stores the start address of the management file information table MNFIT.This address is used in the seek operation for accessing the MNFITtable.

PL_SRPT (play list search pointer table) (FIG. 8)

The play list search pointer table PL_SRPT records play list searchpointer table information PL_SRPTI and n play list search pointersPL_SRP. PL_SRPTI (play list search pointer table information) (FIG. 8)

The play list search pointer table information PL_SRPTI records thefollowing information for accessing a play list search pointer PL_SRP.

PL_SRP_Ns (number of play list search pointers)

Stores the number of play list search pointers PL_SRP.

PL_SRPT_EA (PL_SRPT end address)

Stores the end address of this play list search pointer table PL_SRPT.

PL_SRP (play list search pointer) (FIG. 8)

Records the following information for accessing the actual play listdata, that is, the user-defined PGC.

PL_TY (play list type)

Stores one of the following values for identifying the play list typeusing the format shown in FIG. 9.

0000b: video only

0001b: still images only

0010b: both video and still images

0011b: audio only

PGCN (PGC number)

Stores the PGC number for the associated play list. The PGC number isthe recording sequence of PGC information in the UD_PGCIT describedbelow.

PL_CREATE_TM (play list creation date/time)

Stores the date and time the play list was created according to theformat shown in FIG. 9.

PRM_TXTI (primary text information)

Stores text information indicative of play list content. For example, ifthe play list is a television program, PRM_TXTI could record the name ofthe show. PRM_TXTI includes an ASCII code field, and a field for thecharacter code set defined by the above-noted CHRS.

IT_TXT_SRPN (IT_TXT_SRP number)

If information indicative of the play list content is recorded as theoptional IT_TXT block in addition to the above-noted primary text, theIT_TXT_SRP number is stored as a link to the IT_TXT recorded inTXTDT_MG. This IT_TXT_SRP number is the recording sequence in TXTDT_MG,described below.

THM_PTRI (thumbnail pointer information)

Stores thumbnail image information for the play list.

THM_PTRI (FIG. 8)

THM_PTRI stores the following information indicating a thumbnail imagelocation.

CN (cell number)

Stores the cell number containing the thumbnail image. The cell numberis the recording sequence of the cell information in the UD_PGCI forthis play list.

THM_PT (thumbnail image pointer)

Stores the presentation time of the video frame used as the thumbnailimage according to the PTM (presentation time) describing format asshown in FIG. 10 if the cell indicated by CN is a video cell. PTM iswritten according to the reference time of the time stamp written in theMPEG program stream.

Stores the still image VOB entry number of the still image used as thethumbnail image according to the S_VOB_ENTN describing format as shownin FIG. 11 if the cell indicated by CN is a still image cell.

M_AVFIT (FIG. 12)

The movie AV file information table M_AVFIT stores managementinformation for the movie AV file RTR_MOV.VRO, and comprises M_AVFITI,M_VOB_STI, and M_AVFI.

M_AVFITI (movie AV file information table information) (FIG. 12)

Stores the following information for accessing M_VOB_STI and M_AVFI.

M_AVFI_Ns (movie AV file information number)

Indicates the number of following AVFI information fields. If 0, no AVFIis present; if 1, an AVFI is present. AVFI presence corresponds to thepresence of movie AV file RTR_MOV.VRO.

M_VOB_STI_Ns (M_VOB_STI number)

Indicates the number of following M_VOB_STI fields.

M_AVFIT_EA (M_AVFIT end address)

Stores the M_AVFIT end address.

M_VOB_STI (movie VOB stream information) (FIG. 12)

Stores the following as movie VOB stream information.

V_ATR (video attributes)

Stores the following video attributes according to the format as shownin FIG. 13.

Video compression mode

Stores one of the following values indicating the video compressionmode.

00b: MPEG_(—)1

01b: MPEG_(—)2

TV system

Stores one of the following values indicating the television system.

00b: 525/60 (NTSC)

01b: 625/50 (PAL)

Aspect ratio

Stores one of the following values indicating the aspect ratio.

00b: 4×3

01b: 16×9

line21_switch_1

Stores one of the following values indicating whether closed captiondata for field 1 is contained in the video stream.

1b: recorded

0b: not recorded

line21_switch_2

Stores one of the following values indicating whether closed captiondata for field 2 is contained in the video stream.

1b: recorded

0b: not recorded

Video resolution

Stores one of the following values indicating the video resolution.

000b: 720×480 (NTSC), 720×576 (PAL)

001b: 702×480 (NTSC), 702×576 (PAL)

010b: 352×480 (NTSC), 352×576 (PAL)

011b: 352×240 (NTSC), 352×288 (PAL)

100b: 544×480 (NTSC), 544×576 (PAL)

101b: 480×480 (NTSC), 480×576 (PAL)

AST_Ns (audio stream number)

Stores the number of audio streams recorded to the corresponding VOB.

SPST_Ns (still picture stream number)

Stores the number of still picture streams recorded to the correspondingVOB.

A_ATR0 (audio stream 0 attributes)

Stores the following attributes for the audio recorded to audio stream 0using the format as shown in FIG. 13.

Audio coding mode

Stores one of the following values indicating the audio compressionmethod.

000b: Dolby AC-3

001b: MPEG audio without an extension stream

010b: MPEG audio with an extension stream

011b: linear PCM

Preference flag

Stores one of the following values indicating user preferenceinformation for the audio channel.

00b: not applicable

01b: audio channel 1

10b: audio channel 2

For example, if audio channel 1 is in Japanese, audio channel 2 is inEnglish, and the user prefers to listen in English, this preference flagis set to 10b by the user.

Application Flag

Stores one of the following values indicating the audio application.

00b: not applicable

01b: plural audio channel configurations are mixed

10b: enhancement channel included

Note that a value of 01b indicating plural audio channel configurationsare mixed means, for example, that two or more audio streams ofmonaural, stereo, or dual audio (such as in both Japanese and English)are recorded to the AV stream on separate time bases.

The enhancement channel is an enhanced audio channel for the visuallyimpaired.

Quantization/DRC

Stores one of the following values for identifying whether dynamic rangecontrol (DRC) information is present.

00b: DRC not contained in MPEG stream

01b: DRC contained in MPEG stream

If LPCM is used, the following value is stored to identify thequantization level.

00b: 16 bit

fs

The following value is stored to identify the sampling frequency.

00b: 48 kHz

Number of Audio channels

Stores one of the following values indicating the number of audiochannels.

0000b: 1 channel (monaural)

0001b: 2 channel (stereo)

0010b: 3 channel

0011b: 4 channel

0100b: 5 channel

0101b: 6 channel

0110b: 7 channel

0111b: 8 channel

1001b: 2 channel (dual monaural)

Dual monaural refers, for example, to a bilingual recording with main(e.g., Japanese) and sub (e.g., English) channels, both of which aremonaural.

Bitrate

Stores one of the following values indicating the bitrate.

0000 0001b: 64 kbps

0000 0010b: 89 kbps

0000 0011b: 96 kbps

0000 0100b: 112 kbps

0000 0101b: 128 kbps

0000 0110b: 160 kbps

0000 0111b: 192 kbps

0000 1000b: 224 kbps

0000 1001b: 256 kbps

0000 1010b: 320 kbps

0000 1011b: 384 kbps

0000 1100b: 448 kbps

0000 1101b: 768 kbps

0000 1110b: 1536 kbps

What is important here is that if the corresponding audio stream is anMPEG audio stream with an extension stream, only the bitrate of the basestream, not including the extension stream, is recorded. This is becausecompression using a VLC technique is used for the extension stream, andthe extension stream therefore cannot be defined using a fixed bitrateas above.

A_ATR1 (audio stream 1 attributes)

Stores the following attributes of audio stream 1 using the format asshown in FIG. 13. Note that these attributes are defined using the samefields used with A_ATR0 and described above, and further description isthus omitted here.

As shown in FIG. 43, if there are two audio streams (audio stream 1 andaudio stream 2) for a single AV stream, A_ATR0 is used for audio stream1 management information, and A_ATR1 is used for audio stream 2management information. Because A_ATR0 and A_ATR1 are identical instructure, A_ATR0 shown on the bottom in FIG. 13 is also applicable toA_ATR1.

One possible application for two audio streams is to broadcast abaseball game, for example, with announcer commentary for one teambroadcast in stereo on audio stream 1, and the announcer commentary forthe other team broadcast in stereo on audio stream 2.

If there is only one audio stream, that is, audio stream 1 in this caseas shown in FIG. 44, A_ATR0 is used for the audio stream 1 managementinformation while A_ATR1 is left blank or as initialized.

Furthermore, if audio streams 1 and 2 are both recorded for a single AVstream, A_ATR0 is used for audio stream 1 management information, andA_ATR1 is used for audio stream 2 management information. By setting thepreference flag to 10b in A_ATR1 as shown in FIG. 45, audio channel 2,that is, the subchannel, can be designated the preferred channel andselected with priority to audio channel 1. Furthermore, by setting theapplication flag to 01b it is known that a plurality of audio channelsare mixed. By further setting the number of audio channels to 1001b, itis known that two channel (dual monaural) audio is the preferred mode.Which is the preferred or representative mode when there are pluralmodes can be detected by, for example, comparing the total time of eachmode and selecting the mode with the longest time, or sending a code inthe broadcast signal indicating a preselected preferred mode.

SP_ATR (subpicture attribute)

Records the subpicture attribute information shown below according tothe format as shown in FIG. 14.

Application Flag

Stores one of the following values indicating the application type.

00b: not applicable

01b: caption

10b: animation

SP_PLT (subpicture color palette)

Records the subpicture color palette information using the format shownin FIG. 14.

M_AVFI (FIG. 15)

The movie AV file information M_AVFI comprises the following informationfor accessing a movie VOB: M_AVFI_GI, M_VOBI_SRP, and M_VOBI.

M_AVFI_GI (movie AV file general information) (FIG. 15)

Stores the movie VOB information search pointer count M_VOBI_SRP_Ns.

M_VOBI_SRP_Ns (movie VOB information search pointer number)

Records the number of movie VOB information search pointers M_VOBI_SRP.

M_VOBI_SRP (movie VOB information search pointer) (FIG. 15)

Stores address information for accessing each M_VOBI.

M_VOBI_SA (movie VOB information start address)

Stores the M_VOBI start address used for a seek operation accessing thecorresponding VOBI information.

M_VOBI (movie VOB information) (FIG. 16)

Stores the following movie VOB management information: M_VOB_GI, SMLI,AGAPI, TMAPI, and CP_MNGI.

M_VOB_GI (general information) (FIG. 16)

Records the following general information relating to a movie VOB.

VOB_TY (VOB type)

Stores VOB attributes according to the format as shown in FIG. 17.

TE

Stores one of the following values indicating the VOB status.

0b: normal

1b: temporarily or partially deleted

A0_STATUS

Stores one of the following values indicating the status of to audiostream 0.

00b: original state

01b: overwritten

A1_STATUS

Stores one of the following values indicating the status of audio stream1.

00b: original state

01b: overwritten

10b: dummy for additional audio content

11b: additional audio content added

APS

Stores one of the following values indicating the analog copy preventioncontrol signal state.

00b: analog copy protection not enabled

01b: type 1

10b: type 2

11b: type 3

SML_FLG

Stores one of the following values indicating whether the VOB is to beseamlessly reproduced with the preceding VOB.

0b: seamless reproduction not possible

1b: seamless reproduction possible

A0_GAP_LOC

Stores one of the following values indicating the presence of an audioreproduction gap in audio stream 0, and identifying the VOBU to whichthe audio reproduction gap is multiplexed.

00b: no audio reproduction gap recorded

01b: audio reproduction gap multiplexed to first VOBU

10b: audio reproduction gap multiplexed to second VOBU

11b: audio reproduction gap multiplexed to third VOBU

A1_GAP_LOC

Stores one of the following values indicating the presence of As anaudio reproduction gap in audio stream 1, and identifying the VOBU towhich the audio reproduction gap is multiplexed.

00b: no audio reproduction gap recorded

01b: audio reproduction gap multiplexed to first VOBU

10b: audio reproduction gap multiplexed to second VOBU

11b: audio reproduction gap multiplexed to third VOBU

VOB_REC_TM (VOB recording date/time)

The date and time the VOB was recorded is stored in the same format usedfor PL_CREATE_TM shown in FIG. 9. What is important to note here is thatthis indicates the date/time that the first video presentation frame ofthe VOB was recorded. If the first video frame is changed by editing ordeletion, this VOB_REC_TM value must be updated. It should be furthernoted that the date/time of recording can be displayed synchronized tothe VOB presentation similarly to the way a date/time is displayed onthe viewfinder of a video camcorder by simply adding the time elapsed inthe VOB to the time stored as VOB_REC_TM.

VOB_REC_TM_SUB (VOB recording date/time difference information)

This field is used to absorb error in a VOB_REC_TM field that has beenupdated because the first video frame in the VOB was changed by VOBediting or deletion. As shown in FIG. 9, VOB_REC_TM is only accurate tothe second. This means that if the video was edited or deleted at theframe or field level (precision), the recording time cannot be expressedwith sufficient accuracy using only VOB_REC_TM. This field is thereforeused to adjust for any difference.

M_VOB_STIN (M_VOB_STI number)

Stores the M_VOB_STI number corresponding to the VOB. This M_VOB_STInumber is the recording sequence in the above-noted M_VOB_STI table.

VOB_V_S_PTM (VOB video start PTM)

Stores the VOB presentation start time based on the same reference timeas the time stamp of the video stream.

VOB_V_E_PTM (VOB video end PTM)

Stores the VOB presentation end time based on the same reference time asthe time stamp of the video stream. It should be noted that the timestamp of the stream indicates the presentation start time of the frame,but this VOB_V_E_PTM field records the presentation end time, that is,the sum of the start time plus the frame presentation period.

SMLI (seamless information) (FIG. 16)

SMLI stores the following information required for seamless reproductionwith the preceding VOB. Note that this field is only recorded when theabove-noted SML_FLG is 1b.

VOB_FIRST_SCR

Stores the SCR of the first pack in the VOB.

PREV_VOB_LAST_SCR

Stores the SCR of the last pack in the previous VOB.

AGAPI (audio gap information) (FIG. 16)

AGAPI records the following information required for the decoder toprocess an audio reproduction gap. This field is only recorded when avalue other than 00b is written to the above-noted AO_GAP_LOC orA1_GAP_LOC.

VOB_A_STP_PTM (VOB audio stop PTM)

Records the time of the audio reproduction gap, that is, the time atwhich the decoder is to temporarily stop audio reproduction. This timeis recorded using the same reference time as the stream time stamp.

VOB_A_GAP_LEN (VOB audio gap length)

Records the length of the audio reproduction gap in 90 kHz precision.

CP_MNGI (copy management information) (FIG. 16)

Records the copy management information for the corresponding VOB, andcomprises CPG_STATUS and CPGI.

CPG_STATUS (copy protection status)

Stores a value used for VOB copy protection. CPG_STATUS indicateswhether content can be freely copied or whether only a first generationcopy can be made.

CPGI (copy protection information)

Records the copy protection information applied to the correspondingVOB.

TMAPI (time map information) (FIG. 18)

The time map information comprises TMAP_GI, TM_ENT, and VOBU_ENT fields.

TMAP_GI (FIG. 18)

The general TMAP information TMAP_GI comprises TM_ENT_Ns, VOBU_ENT_Ns,TM_OFS, and ADR_OFS fields as described below.

TM_ENT Ns (TM_ENT number)

Records the number of TM_ENT fields in the TMAPI block as describedbelow.

VOBU_ENT_Ns (VOBU_ENT number)

Records the number of VOBU_ENT fields in the TMAPI block as describedbelow.

TM_OFS (time offset)

Records the time map offset with the video field precision.

ADR_OFS (address offset)

Records the offset in the first AV field in the VOB.

TM_ENT (time entry) (FIG. 18)

A time entry comprises the following fields as access point informationat a constant time interval TMU. If the video format is NTSC, the TMU is600 video fields; if PAL, it is 500 video fields.

VOBU_ENTN (VOBU_ENT number)

Records the entry number of a VOBU containing the time (TMU×(N−1)+TM_OFSfor the N-th TM_ENT) indicated by the TM_ENT.

TM_DIFF (time difference)

Records the difference between the time indicated by this TM_ENT and thepresentation start time of the VOBU pointed to by VOBU_ENTN.

VOBU_ADR (VOBU address)

Records the start address in the VOB of the VOBU pointed to byVOBU_ENTN.

VOBU_ENT (FIG. 19)

The VOBU entry (VOBU_ENT) has the fields shown below for thecorresponding VOBU. The fields are formatted as shown in FIG. 19. Thetime and address information required to access a desired VOBU can beobtained by simply adding the following fields in sequence.

1STREF_SZ

Stores the number of packs from the first pack in the VOBU to the packcontaining the last data block of the first I-picture in the VOBU.

VOBU_PB_TM

Records the playback time of this VOBU.

VOBU_SZ

Records the data size of this VOBU.

S_AVFIT (FIG. 20)

The still image AV file information table comprises the followingmanagement information fields for the still image AV file RTR_STO.VRO:S_AVFITI, S_VOB_STI, S_AVFI.

S_AVFITI (still image AV file information table information) (FIG. 20)

Stores the following information required to access S_VOB_STI andS_AVFI. S_AVFI_Ns (still image AV file information number)

This is a value of either 0 or 1. This value corresponds to the numberof still image AV files, that is, RTR_STO.VRO file presence.

S_VOB_STI_Ns (still image VOB stream information number)

Records the number of S_VOB_STI described below.

S_AVFI_EA (still image AV file information end address)

Records the S_AVFI end address.

S_VOB_STI (still image VOB stream information) (FIG. 20)

Records the following still image VOB stream information.

V_ATR (video attributes)

Information recorded as the video attributes are the Video compressionmode, TV system, Aspect ratio, and Video resolution. These fields are asdescribed above with reference to the video attributes V_ATR of theM_VOB_STI.

OA_ATR (audio stream attributes)

The audio stream attribute fields are: Audio coding mode, ApplicationFlag, Quantization/DRC, fs, Number of Audio channels. These are also asdescribed above with reference to the A_ATR0 fields of the M_VOB_STI.

SP_ATR (subpicture attribures)

The Application Flag is recorded for the subpicture attributes. Thisfield is the same as SP_ATR described above with reference to M_VOB_STI.

SP_PLT (subpicture color palette)

Stores the color palette information for subpictures. The format is asdescribed with reference to the SP_PLT of M_VOB_STI.

S_AVFI (still image AV file information) (FIG. 23)

Comprises the following fields required to access a still image VOG:S_AVFI_GI, S_VOGI_SRP, and S_VOGI.

S_AVFI_GI (FIG. 23)

General still image AV file information S_AVFI_GI records S_VOGI_SRP_Ns.

S_VOGI_SRP_Ns (still image VOB group search pointer number)

Records the number of S_VOGI_SRP fields described below.

S_VOGI_SRP (still image VOB group information search pointer) (FIG. 23)

Records S_VOGI_SA.

S_VOGI_SA (still image VOB group information start address) records thestart address of this S_VOGI.

S_VOGI (FIG. 23)

The still image VOB group information S_VOGI comprises the followingstill image VOB management information fields: S_VOG_GI, S_VOB_ENT,CP_MNGI.

S_VOG_GI (FIG. 23)

General still image VOB group information S_VOG_GI records the followingfields as general information relating to the still image VOB group.

S_VOB_Ns (still image VOB number)

Records the number of still image VOBs in the still image VOB group.

S_VOB_STIN (S_VOB_STI number)

Records the S_VOB_STI number storing the still image VOB streaminformation. This S_VOB_STI number is the recording sequence in theS_VOB_STI table.

FIRST_VOB_REC_TM (first VOB recording date/time)

Records the recording date/time information of the first still image VOBin the still image VOB group.

LAST_VOB_REC_TM (last VOB recording date/time)

Records the recording date/time information of the last still image VOBin the still image VOB group.

S_VOG_SA (still image VOB group start address)

Records the start address of the still image VOB group in theRTR_STO.VRO file.

CP_MNGI (copy management information)

Records copy management information relating to the corresponding stillimage VOB group. The fields thereof are the same as the above-describedCP_MNGI for movie VOB information M_VOBI. S_VOB-ENT (FIG. 24)

Still image VOB entries S_VOB_ENT are defined as either type A or type Bas described below according to whether there is audio recorded forindividual still image VOBs in the still image VOB group.

S_VOB_ENT (Type A) (FIG. 24)

Type A comprises the fields S_VOB_ENT_TY and V_PART_SZ, defined asfollows.

S_VOB_ENT_TY (still image VOB entry type)

Still image VOB type information is formatted as shown in FIG. 25.

MAP_TY

Stores one of the following values for identifying type A or type B.

00b: type A

01b: type B

TE

Stores one of the following values indicating the status of the stillimage VOB.

0b: normal

1b: temporarily or partially deleted

SPST_Ns

Stores the number of subpicture streams in the still image VOB.

V_PART_SZ (video part size)

Stores the data size of the video part of the still image VOB.

S_VOB_ENT (Type B) (FIG. 24)

In addition to S_VOB_ENT_TY and V_PART_SZ fields, type B also hasA_PART_SZ and A_PB_TM fields as defined below.

S_VOB_ENT_TY (still image VOB entry type)

Records the type of the still image VOB. These fields are as describedabove with reference to type A.

V_PART_SZ (video part size)

Stores the data size of the video part of the still image VOB.

A_PART_SZ (audio part size)

Stores the data size of the audio part of the still image VOB.

A_PB_TM (audio playback time)

Stores the playback time (length) of the audio part of the still imageVOB.

UD_PGCIT (FIG. 26)

The user-defined PGC information table comprises the following fields:UD_PGCITI, UD_PGCI_SRP, and UD_PGCI.

UD_PGCITI (FIG. 26)

The user-defined PGC information table information UD_PGCITI records thefollowing fields constituting the user-defined PGC information table.

UD_PGCI_SRP_Ns (user-defined PGC information search pointer number)

Records the number of UD_PGCI_SRP fields.

UD_PGCIT_EA (user-defined PGC information table end address)

Records the UD_PGCIT end address.

UD_PGCI_SRP (FIG. 26)

The user-defined PGC information search pointer UD_PGCI_SRP records theUD_PGCI_SA field.

UD_PGCI_SA (user-defined PGC information start address)

Records the UD_PGCI start address. This address is used to seek andaccess the PGCI.

UD_PGCI (FIG. 26)

The detailed structure of the user-defined PGC information is describedfurther below under the PGC information PGCI.

ORG_PGCI (FIG. 5)

The detailed structure of the original PGC information is describedfurther below under the PGC information PGCI.

TXTDT_MG (FIG. 27)

The text data management field TXTDT_MG comprises TXTDTI, IT_TXT_SRP,and IT_TXT fields as described below.

TXTDTI (FIG. 27)

Text data information TXTDTI comprises the following fields: CHRS,IT_TXT_SRP_Ns, TXTDT_MG_EA.

CHRS (character set code)

Records the character set code used for IT_TXT.

IT_TXT_SRP_Ns (IT_TXT search pointer number)

Records the number of IT_TXT_SRP fields.

TXTDT_MG_EA (text data management end address)

Records the end address of the TXTDT_MG block.

IT_TXT_SRP (FIG. 27)

The IT_TXT search pointer IT_TXT_SRP records the following informationfor accessing IT_TXT.

IT_TXT_SA (IT_TXT start address)

Records the IT_TXT start address. This address is used to seek andaccess the IT_TXT block.

IT_TXT_SZ (IT_TXT size)

Records the IT_TXT data size. A desired IT_TXT block can be read byreading this amount of data.

IT_TXT (FIG. 27)

IT_TXT comprises one or more sets of three fields: identification codeIDCD, the text TXT corresponding to that ID code, and an end code TMCDdefining the end of the set. If there is no TXT field for an IDCD, theTXT field can be omitted and IDCD and TMCD recorded as one set. ValidIDCD values are defined as follow.

Genre codes

30h: movie

31h: music

32h: drama

33h: animation

34h: sports

35h: documentary

36h: news

37h: weather

38h: educational

39h: hobby

3Ah: entertainment

3Bh: performing arts (plays, opera)

3Ch: shopping Input source codes

60h: broadcasting station

61h: camcorder

62h: photograph

63h: memo

64h: other

PGCI (FIG. 28)

Original program chain information ORG_PGCI and user-defined programchain information UD_PGCI have a common data structure collectivelyreferred to as program chain information PGCI. PGCI comprises thefollowing fields: PGC_GI (program chain general information), PGI(program information), CI_SRP (cell information search pointer), and CI(cell information).

PGC-GI (FIG. 28)

PGC_GI (PGC general information) comprises the fields PG_Ns (programnumber) and CI_SRP_Ns (cell information search pointer number) asgeneral information about the PGC. These fields are described furtherbelow.

PG_Ns (program number)

Records the number of programs in the PGC. If a user-defined PGC, thisfield is 0 because there is no program.

CI_SRP_Ns (CI_SRP number)

Records the number of cell information search pointers CI_SRP, describedbelow.

PGI (FIG. 28)

PGI (program information) comprises the following fields as describedbelow: program type PG_TY, cell number C_Ns, primary text informationPRM_TXTI, IT_TXT_SRPN, and THM_PTRI.

PG_TY (program type)

Records the following information formatted as shown in FIG. 29.

Protect (protected)

0b: normal

1b: protected

C_Ns (cell number)

Records the cell number in the program.

PRM_TXTI (primary text information)

Records the text information describing program content. For furtherdetails, see the above-noted PL_SRPT.

IT_TXT_SRPN (IT_TXT_SRP number)

If IT_TXT containing program content information is recorded in additionto the primary text noted above, the IT_TXT_SRP number recorded inTXTDT_MG is stored to this field.

THM_PTRI (thumbnail image pointer information)

Records the thumbnail image information representing this program.Details about the THM_PTRI are identical to the above-noted THM_PTRI ofPL_SRPT.

CI_SRP (FIG. 28)

The cell information search pointer (CI_SRP) records address informationrequired for accessing this cell information.

CI_SA (cell information start address)

Records the start address of the cell information. The cell is accessedby seeking this address.

CI (FIG. 30)

CI (cell information) is one of two types: M_CI for movies, or S_CI forstill image.

M_CI (FIG. 30)

M_CI (movie cell information) comprises the following fields: M_C_GI andM_C_EPI.

M_C_GI (FIG. 30)

M_C_GI (movie cell general information) contains the following basicinformation for each cell.

C_TY (cell type)

Records the following information formatted as shown in FIG. 31 foridentifying movie cells and still image cells.

C_TY1

000b: movie cell

001b: still image cell

M_VOBI_SRPN (movie VOB information search pointer number)

Records the search pointer number of the movie VOB informationcorresponding to this cell. To access the stream data corresponding tothis cell, it is first necessary to access the movie VOB informationsearch pointer number indicated by this field.

C_EPI_Ns (cell entry point information number)

Records the number of entry points in this cell.

C_V_S_PTM (cell video start time)

Records the playback start time of the cell using the format shown inFIG. 10.

C_V_E_PTM (cell video end time)

Records the playback end time of the cell using the format shown in FIG.10. Used in conjunction with C_V_S_PTM to define the valid cell periodwithin the corresponding VOB.

M_C_EPI (FIG. 32)

M_C_EPI (movie cell entry point information) is categorized as Type A orType B based on the presence of primary text. M_C_EPI (Type A) (FIG. 32)

M_C_EPI (Type A) contains the following information indicative of anentry point.

EP-TY (entry point type)

Records the following information formatted as shown in FIG. 33 foridentifying the entry point type.

EP_TY1

00b: Type A

01b: Type B

EP_PTM (entry point time)

Records the time at which the entry point is set according to the formatas shown in FIG. 10.

M_C_EPI (Type B) (FIG. 32)

In addition to the same EP_TY and EP_PTM fields of Type A, M_C_EPI (TypeB) has a PRM_TXTI field as described below.

PRM_TXTI (primary text information)

Records text information describing the content of the locationindicated by the entry point. Details of this information are asdescribed in the above-noted PL_SRPT.

S_CI (FIG. 30)

S_CI (still image cell information) comprises S_C_GI and S_C_EPI fields.

S_C_GI (FIG. 30)

S_C_GI (still image cell general information) contains the basic cellinformation described below.

C_TY (cell type)

Records information for identifying movie cells and still image cells.This cell type information is as described above with reference to amovie cell.

S_VOGI_SRPN (still image VOB group information search pointer number)

Records the search pointer number of the still image VOB groupinformation for the cell. To access the stream data corresponding to thecell, it is first necessary to access the still image VOB groupinformation search pointer number indicated by this field.

C_EPI_Ns (cell entry point information number)

Records the number of entry points in this cell.

S_S_VOB_ENTN (starting still image VOB number)

Records the still image VOB number from which cell reproduction startsaccording to the format as shown in FIG. 11. The still image VOB numberis the sequence number in the S_VOG pointed to by the above-notedS_VOGI_SRPN.

E_S_VOB_ENTN (end still image VOB number)

Records the still image VOB number at which cell reproduction endsaccording to the format as shown in FIG. 11. The still image VOB numberis the sequence number in the S_VOG pointed to by the above-notedS_VOGI_SRPN. It should be noted that the valid cell period in the S_VOGto which the cell belongs is defined by this field in conjunction withS_S_VOB_ENTN.

S_C_EPI (FIG. 32)

S_C_EPI (still image cell entry point information) is categorized asType A or Type B depending upon the presence of primary text.

S_C_EPI (Type A) (FIG. 32)

S_C_EPI (Type A) contains the following information indicative of anentry point.

EP_TY (entry point type)

Records the following information formatted as shown in FIG. 33 foridentifying the entry point type.

EP_TY1

00b: Type A

01b: Type B

S_VOB_ENTN (still image VOB entry number)

Records the still image number-in which the entry point is set accordingto the format as shown in FIG. 11.

S_C_EPI (Type B) (FIG. 32)

In addition to the same EP_TY and S_VOB_ENTN fields of Type A, S_C_EPI(Type B) has a PRM_TXTI as described below.

PRM TXTI (primary text information)

Records text information describing the content of the locationindicated by the entry point. Details of this information are asdescribed in the above-noted PL_SRPT.

Configuration of a DVD Recorder

The configuration of a DVD recorder is described next below withreference to FIG. 40.

As shown in the figure, this DVD recorder comprises a user interface7801 for interaction with the user; a system controller 7802 forhandling overall management and control of the recorder; an input block7803 comprising an A/D converter for audio and video input to therecorder; an encoder 7804; an output section 7805 for audio and videooutput; a decoder 7806 for MPEG stream decoding; track buffer 7807; anddrive 7808.

Operation of a DVD Recorder

The basic recording and reproduction operation of a DVD recorder shownin FIG. 40 is described next below.

Before recording starts, the input block 7803, encoder 7804, and trackbuffer 7807 are initialized by a command from the system controller7802. Audio and video data input to the input block 7803 are A/Dconverted and passed to the encoder 7804. The encoder 7804 compressesand multiplexes the video and audio data to generate an MPEG systemstream, which it then passes to the track buffer 7807. Data is thenpassed sequentially from the track buffer 7807 to the drive forrecording to DVD-RAM disc.

A reproduction operation is described next.

After inserting a DVD-RAM disc to the disc player for reproduction, theuser selects the AV stream to be played from among the plural AV streamson the disc. The method whereby the user selects the desired AV streamis described in particular detail below.

As noted above, a plurality of AV streams can be recorded to a singledisc. It is therefore essential that the disc player be able to presentto the user a list of all AV streams currently on the disc.

As also described above each AV stream is managed using video object VOBunits. Video object information VOBI is recorded specifically for eachVOB to record and manage attribute information for each VOB. A sequenceof one or a plurality of VOBs is managed using a program chain PGdefining a hierarchical sequence of VOBs. This program concept isintroduced so that bitstreams representing a linear stream of data canbe managed when recorded for whatever reason as a plurality of AVstreams. This program concept is useful for managing separately recordedscenes as a meaningful sequence of related events. For example, an AVstream of a tug-of-war recorded during morning using a disc camera, andanother AV stream of a relay race recorded in the afternoon could belinked and managed as a single program titled as a “school field day.”Program information PGI is recorded for each program. The titleassociated with a particular program is recorded and managed within theattribute information for that program.

The program is thus a useful unit for recording and reproducing AVcontent in a way that can be easily understood by and presented to theuser, while the video object VOB is the unit whereby these AV streamsare internally managed by the DVD recorder.

Management information as related to the present invention and appliedto actual AV stream data is described next below with reference to FIG.46.

Row L1 in FIG. 46 shows program chain information PGCI. The left blockL1a shows the original program chain information ORG_PGCI required toreproduce an AV stream as it was recorded. The right block L1b and L1cshow the user-defined program chain information UD_PGCI required toreproduce a program chain as edited and defined by the user.

The hierarchical structure of the ORG_PGCI management information isshown in FIG. 5, FIG. 28, and FIG. 30. The hierarchical structure of theUD_PGCI management information is shown in FIG. 5, FIG. 26, FIG. 28, andFIG. 30.

It should be noted that plural UD_PGCI can be recorded to a single disc.The UD_PGCIT (user defined program chain information table) as shown inFIG. 5 is therefore used as a table of these UD_PGCI from which a usercan select a particular UD_PGCI for reproduction.

The title of the first recorded program can be obtained by tracing apath through the management information in the order described belowwith reference to FIG. 46.

S1 in FIG. 5→S2→S3 in FIG. 28.

The second row L2 in FIG. 46 shows the still image VOB managementinformation S_VOBI and movie VOB management information M_VOBI. Up to999 M_VOBI management information blocks 1o can be recorded to anoptical disc. The hierarchical structure of this M_VOBI managementinformation is shown in FIG. 5, FIG. 15, and FIG. 16.

Whether a cell in the program chain information PGCI in row L1 isassociated with any movie VQB management information M_VOBI in row L2can be known from the management information described below.

S1 in FIG. 5→S2→S3 in FIG. 28 (C_Ns is the number of cells in theprogram. By counting the number of cells contained in a program insequence from the first program, the number of a cell contained in thedesired program is obtained. The number of the obtained cell is used asthe cell search pointer CI_SRP#n.)

→S5→S6→S7 (Obtain the cell address based on the cell search pointer.)

→S8 (Obtain the number of the address cell information.)

→FIG. 30, S9 (movie cell information M_CI)

→S10 (movie cell general information M_CGI.)

→S11 (movie VOB information search pointer number M_VOBI_SRPN)

→FIG. 5, S12 (AV file information table)

→FIG. 15, S13→S14→S15 (access the movie VOB information search pointerdetected in S11)

→S16→S17 (determine the movie VOB information start address)

S18→S19

Row L3 in FIG. 46 shows the movie VOB stream information M_VOB_STI.Application Flag and Preference Flag according to the present inventionare written to M_VOB_STI. That is, as shown in FIG. 12, M_VOB_STIcontains audio attributes A_ATR0 and A_ATR1. As shown in FIG. 13, audioattributes A_ATR0 and A_ATR1 contain an Application Flag (b17, b16) andPreference Flag (b19, b18). A maximum 64 M_VOB_STI can be written to oneoptical disc. One M_VOB_STI is allocated to each one M_VOBI, andM_VOB_STI of identical content are often allocated to plural M_VOBI. Inthis case a common M_VOB_STI can be linked to multiple M_VOBI. Forexample, M_VOBI#1 and M_VOBI#2 are linked to a common M_VOB_STI#2 inFIG. 46.

The link between a particular M_VOBI and any particular M_VOB_STI can beknown from management information as described next below.

In the above sequence of steps it was determined in step S19, FIG. 5,what movie VOB management information M_VOBI is linked to what cells inthe program chain information PGCI in FIG. 46. The M_VOB_STI linked tomovie VOB management information M_VOBI is obtained as follows.

FIG. 5, S19→S20→FIG. 16, S21 (M_VOB_STIN indicates a stream informationnumber of the movie VOB).

The Application Flag (b17, b16) and Preference Flag are obtained fromthis M_VOB_STIN as follows.

FIG. 5, S12→FIG. 12, S22→S23→S24

FIG. 47 is a flow chart of a process whereby a DVD-RAM disc is recordedby a DVD recorder according to the present invention. The steps in thisprocess are described below.

Step #1: The disc recorder/player shown in FIG. 40 is initialized. N_AC1memory, N_AC2 memory, AP_FLG1 memory, AP_FLG2 memory, and PR_FLG memoryin the system controller 7802 are initialized. N_AC1 and N_AC2 are fortemporarily recording the number of audio channels in audio stream 1 andaudio stream 2. PR_FLG stores the user's channel preference. Forexample, if dual monaural recordings in Japanese and English arepresent, and the user prefers to listen in English, the Preference Flaginformation indicating that audio channel 2 is should be preferentiallyreproduced is stored temporarily to memory. AP_FLG1 and AP_FLG2 storethe audio stream 1 and audio stream 2 application information, that is,whether a mixed combination of plural audio channels is recorded.Information indicative of, for example, whether monaural, stereo, anddual monaural audio recordings are mixed in the single AV streamselected by the particular M_VOB_STI is temporarily stored in memory. Atypical mixed audio application as shown in FIG. 42 (c) might be a moviebroadcast in Japanese and English using dual monaural channels andcommercials recorded in stereo.

In Step #1 in this example, memory N_AC1 and N_AC2 are initialized to1111b, and AP_FLG1 and AP_FLG2 are initialized to 00b, where “b”indicates binary code. PR_FLG is set to the preset value selected by theuser by means of user interface 7801, or to the default value if no userpreference has been defined.

Step #2: The input block 7803 sends the A/D converted input signal data(note that while both audio and video data is received and converted, wefocus herein on the audio data) and the audio channel informationextracted from the input signal to the encoder 7804.

Step #3: The encoder 7804 encodes the audio data according to the audiodata configuration, sends the encoded audio data and video data, thatis, the encoded AV stream data, to the track buffer, and sends the audiochannel information to the system controller 7802.

Step #4: The system controller 7802 converts the received audio channelinformation for audio stream 1 or audio stream 2 to the above-noted4-bit ID code, and buffers this data to N_AC1 or N_AC2. For example, ifthe ID code is 0001b, the audio channel information is known to be twochannel (stereo).

Step #5: If the audio channel for audio stream 1 or audio stream 2differs within the same AV stream from the audio channel informationpreviously received by the system controller 7802, AP_FLG1 or AP_FLG2 isset to 01b. For example, if different audio channel configurations aremixed within a single audio stream as shown in FIG. 42(c), theApplication Flag is set to 01b as noted above, indicating that the audiostream contains a mixed audio channel configuration.

Step #6: The system controller 7802 controls the drive to sequentiallyread the AV stream data from the track buffer 7807 and record it todisc.

Step #7: Whether there is more data to be input to the same AV stream isthen detected. If there is, the procedure loops back to step #2 andrepeats. If not, it advances to step #8. In other words, step #8 beginswhen recording one AV stream is completed.

Step #8: Recording the movie VOB management information M_VOBI for theAV stream (VOB) that has been completely recorded begins to the RTR.FOfile. It should be noted that most of this management information istemporarily stored in memory by the system controller 7802.

Step #9: Information in N_AC1 memory about the number of audio channelsstored, and information in AP_FLG1 memory indicative of whether a mixedaudio channel configuration is recorded, is recorded to ATR0 in streaminformation M_VOB_STI, that is, to areas b11, b10, b9, and b8, and b7and b16 in the A_ATR0 format shown on the bottom in FIG. 13. Data frommemory N_AC2 and AP_FLG2 is likewise recorded in ATR1 of streaminformation M_VOB_STI.

Step #10: User preference information recorded to PR_FLG memory isrecorded to ATR0 in stream information M_VOB_STI, that is, to areas b19,b18 in the A_ATR0 format shown on the bottom in FIG. 13. Otherinformation is also recorded to complete M_VOB_STI, and recorded to theRTR.IFO file.

Step #11: Cell information CI corresponding to the recorded VOB andprogram information PGI are generated and appended to the end of theoriginal program chain information ORG_PGCI.

As shown in FIG. 50, when a DVD-RAM disc according to the presentinvention is loaded into a disc player, a list of all programs (forexample, television dramas, sitcoms, documentaries, new movies, other)recorded to the DVD-RAM disc is presented by means of the output section7805 for the user to review. The configuration of the audio accompanyingeach program is also indicated in this program list.

FIG. 48 is a flow chart of a process for presenting a program list, andparticularly information relating to the audio content configuration,for the user. The example described below addresses presenting a programlist for an original program, that is, program content not edited by theuser. The steps in this process follow.

Step #20: A counter N for counting the number of programs is reset tozero.

Step #21: Counter N is incremented 1.

Step #22: Program information PGI for the N-th program is read.

Step #23: The title is read from the PRM_TXTI field of the PGI.

Step #24: The cell information CI for the PGI is read to obtain themovie VOB information search pointer number M_VOBI_SRPN.

Step #25: Using M_VOBI_SRPN, the corresponding movie VOB managementinformation M_VOBI is read and the movie VOB stream information numberM_VOB_STIN is detected.

Step #26: Using M_VOB_STIN, A_ATR0 in the movie VOB stream informationM_VOB_STI of the corresponding M_VOB is read, and the Application Flag,Preference Flag, and audio channel count for audio stream 1 aredetected. A_ATR1 is likewise read, and management information is foundtherein the Application Flag, Preference Flag, and audio channel countfor audio stream 2 are also detected.

Step #27: Whether there is a next program information PGI is determined.If there is, the procedure loops back to step #21; if not, the procedureadvances to step #28.

Step #28: Using the title detected in step #23 and the Application Flag,Preference Flag, and audio channel count detected in step #26, a programlist screen is generated and presented. This program list also displaysbased on the information from A_ATR0 whether for audio stream 1 there isa mixed configuration of plural audio channels, whether an enhancementchannel is present, and the number of audio channels. Based on theinformation from A_ATR1, it is also indicated for audio stream 2 whetherthere is a mixed configuration of plural audio channels, whether anenhancement channel is present, and the number of audio channels. Ifboth A_ATR0 and A_ATR1 are present, the program list indicates thatthere are two audio streams available; if only A_ATR0 information ispresent, the program list indicates there is only one audio streamavailable.

Step #29: Referring to the displayed program list, the user selects aprogram by way of user interface 7801.

Step #30: The disc player then plays the selected program.

The process for this is shown in the flow chart of 49 and describedbelow.

A typical program list display is described below with reference to FIG.50.

The numbers 1, 2, 3 on the left side of the display are sequentialprogram numbers. The titles are shown in the middle column.

In this example the program list includes a television drama, overseasdocumentary, and a new movie. This information is stored to the PRM_TXTIfield of the program information PGI of the original program chaininformation ORG_PGCI written to the optical disc.

The third column (including two audio streams, monaural, and stereo, forexample) shows the audio stream configuration of the correspondingprogram. This information relates to the audio stream contained in theVOB referenced from a cell contained in the corresponding program, andis generated and displayed using the ATR0 or ATR1 information recordedto the M_VOB_STI specified by M_VOB_STIN in the VOBI of the VOB. Theuser knows from this information the configuration of the audio streamcontained in the program, and can thus determine what audio streams canbe selected and the typical format of an audio stream when reproduced.

For example, it can be determined before playback begins that if theuser selects the “overseas documentary”, audio stream 1 of the dualmonaural audio content will be reproduced based on the informationrecorded to ATR0, and that in accordance with the Preference Flag ofATR0 storing the user's preference, audio channel 1 (main audio) will bereproduced by default.

Likewise, if the “new movie” is selected, it can be known from theinformation recorded to the Number Of Audio Channels and the ApplicationFlag recorded to ATR0 that audio stream 1 contains a mixture of dualmonaural and other audio content, and that the user's preferencespecified by the Preference Flag is to listen to audio channel 2 (sub)in the representative dual monaural parts of the audio content.

It will thus be obvious that information from ATR0 and ATR1 can bepresented to the user when allowing the user to select the program to bereproduced. The user can thus know basic information about the variouspossible audio stream configurations, such as how many audio streams areavailable, the channel configuration of each audio stream, and whetherthe channel configuration includes multiple modes mixed together, beforea selection is made and playback starts, thus avoiding confusing theuser when playback actually begins.

It is also possible to set for each VOB whether to select audio channel1 or 2 when the audio stream is a dual monaural configuration, and theuser can record using the Preference Flag of ATR0 and ATR1 which audiochannel is preferred.

Moreover, if the disc player has a function for automatically selectingand reproducing the audio channel specified by the Preference Flag of aparticular VOB, the user can preprogram the disc player once with theuser's preferred audio channel selection so that the desired audiochannel will always be automatically selected and played without theuser needing to change the audio channel at all.

The playback operation performed after the user selects the program tobe reproduced is described next below.

The track buffer 7807, decoder 7806, and output section 7805 areinitialized by a command from the system controller 7802, The systemcontroller 7802 then instructs the disc drive to seek the start addressof the AV data in the first VOB of the selected program. The drive thenbegins reading the data and passes the read AV data to the track buffer7807. The decoder 7806 reads data from the track buffer 7807, extractsthe decompressed AV data by applying an MPEG decoding operation, andpasses the decompressed AV data to the output section 7805. The outputsection 7805 DIA converts the data and outputs the resulting analog AVdata to the television or other AV device connected to the outputterminal.

FIG. 49 is a flow chart of a playback process for reproducing a programselected from the presented program list. The steps in this process aredescribed next below.

Step #40: The cell information CI for the program information PGI of theselected program is read to obtain M_VOB_SRPN.

Step #41: The corresponding M_VOBI is read from the detected M_VOB_SRPNto obtain the VOB data read address.

Step #42: M_VOB_STIN is obtained from M_VOBI.

Step #43: Using M_VOB_STIN, the decoder is set to the attributes of thecorresponding VOB stream. It should be noted that the audio streamattributes used to setup decoder operation at this time are the audiostream attributes related to the present invention, such as informationabout the number of audio channels and whether there is a mixedconfiguration of multiple audio channels.

Step #44: If there are two audio streams, one is selected by means ofthe user interface of the disc player. If there are multiple audiochannels in the selected audio stream, or in the audio stream itself ifthere is only one audio stream from the start, and user preferenceinformation is also recorded, the audio channel indicated by the userpreference information is selected. If preference information is notrecorded, a default audio channel, such as audio channel 1, is selected.

Step #45: The decoder is set to the selected audio channel.

Step #46: VOB data is read from the read address, buffered to the trackbuffer, and supplied to the decoder.

Step #47: The decoder decodes the audio channel selected in step #44.

Step #48: Whether there is further VOB data to be read is determined. Ifthere is, the procedure loops back to step #40; if not, the processends.

It should be noted that the preferred embodiment of the invention isdescribed above with reference to a DVD-RAM disc, but it will be obviousto one with ordinary skill in the related art that any rewritableoptical disc can be alternatively used. Also, the invention is notrestricted to optical disc, but can be applied to a hard disk or evendistributable flash memory, i.e., a rewritable, random accessiblestorage medium of sufficient capacity.

In addition, preference information regarding two audio channels of adual monaural configuration are used as the Preference Flag valuesstored to ATR0/ATR1 above, but preference information defining apreferred selection from among plural audio streams can be alternativelyused.

Yet further, the Application Flag information stored to ATR0/ATR1 asdescribed above indicates whether a mixed configuration of plural audiochannels is recorded, or whether an audio enhancement channel for thevisually impaired is recorded. Other possible Application Flag valuesinclude information indicating whether audio in a particular language isrecorded. The DVD recorder as referred to above is also assumed to haveboth recording and playback capabilities in a single unit, but thebenefits of the present invention can also be achieved using a dedicateddisc recorder and a separate dedicated disc player.

Benefits of the Invention

By recording information indicating the type of an audio streamconfiguration contained in AV data recorded to optical disc, meaningfulinformation enabling the user to select a desired AV stream forreproduction can be presented to the user, thereby avoiding userconfusion and making the optical disc and disc player easier to operateand use.

Furthermore, by recording user preference information, it isadditionally possible to provide a disc player capable of automaticallyselecting and reproducing an appropriate audio channel conforming to theuser preference.

Although the present invention has been described in connection with thepreferred embodiments thereof with reference to the accompanyingdrawings, it is to be noted that various changes and modifications willbe apparent to those skilled in the art. Such changes and modificationsare to be understood as included within the scope of the presentinvention as defined by the appended claims, unless they departtherefrom.

What is claimed is:
 1. An optical disc comprising: an area for storing adata stream containing an encoded video stream and at least one encodedaudio stream, and an area for storing management information, saidmanagement information comprising an application flag which indicateswhether a single audio stream includes at least two of the following,(a) dual monaural audio data having first audio channel data and secondaudio channel data, one of which is to be selectively reproduced, (b)stereo audio data having first audio channel data and second audiochannel data, which are to be simultaneously reproduced, and (c)monaural audio data having data for only one audio channel.
 2. Arecording method for recording an optical disc comprising an area forstoring a data stream containing an encoded video stream and at leastone encoded audio stream, and an area for storing managementinformation, said recording method comprising: detecting whether asingle audio stream comprises at least two of the following, (a) dualmonaural audio data having first audio channel data and second audiochannel data, one of which is to be selectively reproduced, (b) stereoaudio data having first audio channel data and second audio channeldata, which are to be simultaneously reproduced, and (c) monaural audiodata having data for only one audio channel; and recording anapplication flag to the area for storing management informationaccording to the detection result.
 3. A recording apparatus forrecording an optical disc comprising an area for storing a data streamcontaining an encoded video stream and at least one encoded audiostream, and an area for storing management information, said recordingapparatus comprising: detection means for detecting whether a singleaudio stream comprises at least two of the following, (a) dual monauralaudio data having first audio channel data and second audio channeldata, one of which is to be selectively reproduced, (b) stereo audiodata having first audio channel data and second audio channel data,which are to be simultaneously reproduced, and (c) monaural audio datahaving data for only one audio channel; and recording means forrecording an application flag to the area for storing managementinformation according to the detection result.
 4. A playback method forreproducing an optical disc comprising an area for storing a data streamcontaining an encoded video stream and at least one encoded audiostream, and an area for storing management information, said managementinformation comprising an application flag which indicates whether asingle audio stream includes at least two of the following, (a) dualmonaural audio data having first audio channel data and second audiochannel data, one of which is to be selectively reproduced, (b) stereoaudio data having first audio channel data and second audio channeldata, which are to be simultaneously reproduced, and (c) monaural audiodata having data for only one audio channel; the playback methodcomprising: reading the application flag from the area for storingmanagement information; detecting according to the application flagwhether the single audio stream contains at least two of said audio data(a), (b) and (c).
 5. A playback apparatus for reproducing an opticaldisc comprising an area for storing a data stream containing an encodedvideo stream and at least one encoded audio stream, and an area forstoring management information, said management information comprisingan application flag which indicates whether a single audio streamincludes at least two of the following, (a) dual monaural audio datahaving first audio channel data and second audio channel data, one ofwhich is to be selectively reproduced, (b) stereo audio data havingfirst audio channel data and second audio channel data, which are to besimultaneously reproduced, and (c) monaural audio data having data foronly one audio channel; the playback apparatus comprising: means forreading the application flag from the area for storing managementinformation; and means for detecting according to the application flagwhether the single audio stream contains at least two of said audio data(a), (b) and (c).